This document discusses the role of customers in service delivery. It notes that customers can both enhance and detract from satisfaction through their interactions. Customers participate in the service delivery process and can act as "partial employees" contributing resources. They can also contribute to quality and their own satisfaction by providing feedback or performing their role well. However, customers may lack understanding of their role or interfere with others. The document provides frameworks for understanding different levels of customer participation and strategies businesses can use to enhance participation, such as defining customer jobs and managing the customer mix.